1. Field of the Invention
The present invention relates to a lens barrel and a camera provided with a lens barrel, and more particularly to a camera provided with a lens barrel that is capable of both zooming and focusing. Alternatively, the present invention relates to a camera provided with a taking optical system and a finder optical system, or to a lens barrel for use in such a camera. Alternatively, the present invention relates to a camera provided with a lens barrel having two or more movable segments.
2. Description of the Prior Art
Conventionally, a lens barrel that is designed to be capable of both zooming and focusing is provided with separate zooming and focusing mechanisms. For this reason, in order to allow the two mechanisms to operate independently, it is essential to design a construction in which the two mechanisms do not interfere with each other. Moreover, since the two mechanisms each require separate components, such a lens barrel inevitably requires a larger number of components. Furthermore, since the two mechanisms need to be accommodated, there is a limit to the reduction of the size of such a lens barrel.
On the other hand, in a camera, a taking optical system and a finder optical system are conventionally provided separately. Alternatively, the finder optical system is formed by splitting, in the camera main body, a luminous flux passing through the taking optical system and directing a portion of the luminous flux toward the finder optical system. For these reasons, in the former case, a large parallax arises between the taking optical system and the finder optical system, and, in the latter case, a mechanism for splitting the luminous flux is additionally necessary inside the camera main body.
Furthermore, in a lens barrel having two or more movable segments or in a camera provided with such a lens barrel, great care needs to be taken, when the lens barrel is moved out, not to cause camera shakes due to unstable weight balance of the camera.